Tag: maintenance

MetService had warned of thunderstorms, and on a Friday afternoon earlier this month the rain arrived as promised. Within minutes, two tenants at one of the commercial buildings we look after were on the phone. The ground floor tenant had water coming through the ceiling. The tenant upstairs reported water coming in from the gutter above their office.

Nobody was hurt and nothing was damaged. But the cause turned out to be different from what we, and most people, would have expected, and the fix is a good example of why it pays to investigate before reaching for the obvious answer.

On the day

We were on site by late afternoon. Downstairs, there were only a few drips by then. The same ceiling had leaked before, and because the concrete slab above is porous, water tends to find its way to the same low points each time. We asked the tenant to move anything valuable away from those spots, just in case.

Upstairs, the tenant had already done exactly the right things. Their server room sits directly under the gutter, so they had covered the equipment with plastic sheeting and lifted ceiling tiles so any water could drain somewhere harmless. A few towels were soaking up small puddles in the corridor and bathroom. It was under control.

On the roof, a little debris had blown into the gutter, and under the air conditioning platform we found an old piece of membrane, a rag and a bucket lid. They came out straight away. By then it was after 5pm on a Friday, the weather was unsettled, and no height safety team was available at short notice, so we made the site safe, asked the upstairs tenant to keep buckets ready to protect the tenant below, and came back with a roofing contractor the following week.

What we actually found

Debris looked like the obvious culprit, but the full inspection told a different story.

The gutter guards had done their job. The debris was sitting on top of them, not in the gutter, and nothing was blocked anywhere along the run, at the outlet through the parapet wall, or at the rain head.

The real problem was capacity. The whole length of gutter drains through a single rain head, and the storm dropped a large amount of rain in a very short time. Water simply built up faster than one outlet could carry it away. The brush style gutter guards, while keeping the gutter clear, may also have slowed the water on its way out.

The fix

Rather than simply clearing the gutter and hoping for the best, we worked with the roofing contractor on a fix that deals with the cause:

• A second downpipe partway along the gutter, roughly halving the amount of water that has to reach the single rain head.
• Replacing the brush style gutter guards with a low profile mesh designed to let most of the water straight through while still keeping debris out.

Because this is an older building with heritage requirements, the plan was checked and approved by the building’s heritage adviser before any work was booked. The new external pipe will be finished in the approved colour for the site, and the noisiest work is being scheduled early in the morning, before the office above is busy.

Older buildings rarely have textbook answers. This is a process of elimination rather than a guaranteed cure, but the reasoning behind it is sound, and we expect it to make a real difference in the next big downpour.

Eight checks before the next storm

1. Check capacity, not just cleanliness

A perfectly clean gutter can still overflow if it cannot carry the water away fast enough. Many older buildings were designed for less intense rain than Auckland has seen in recent years. If a gutter overflows in heavy rain even when it is clear, ask whether it has enough outlets for the roof area it serves.

2. One outlet is a single point of failure

Rain heads and the outlets through parapet walls are where water backs up first. A long gutter draining to one outlet has no margin for error. Check where your gutters drain to, and how many outlets each one has.

3. Choose gutter guards for flow as well as debris

Gutter guards are worth having, but they are not all the same. Some types keep leaves out well but slow the water down. If you are fitting or replacing them, ask how much water they let through, not just how much debris they keep out.

4. Find the cause before choosing the fix

Debris looked like the answer here, and clearing it would have felt like job done. It would not have stopped the next overflow. A proper inspection, sometimes over more than one visit, saves money on fixes that do not work.

5. Walk the roof after every contractor visit

Rags, offcuts, lids and old membrane left behind after other work can end up in drains and outlets. A quick roof walk at the end of each job, before the contractor signs off, costs very little.

6. Know what sits under your gutters

Server rooms, electrical cupboards, stock rooms and lift equipment are the places where water does the most damage. If a tenant or owner has something sensitive directly below a gutter or roof outlet, make sure they know, and have a plan for heavy rain.

7. Agree who does what in a downpour

In a multi level building, the people upstairs are often best placed to stop water reaching the people below, with buckets, towels and someone to empty them. Agreeing this before storm season saves confusion on the day.

8. Do not rush roof work in bad weather

A wet roof edge late on a Friday is not the place for a quick fix. Make the area safe, contain the water, and come back in daylight with a team that has the right height safety equipment.

A small cost compared with the alternative

A roof and gutter check before summer storm season is one of the cheapest pieces of maintenance a building can have. Water damage, damaged equipment and insurance claims cost far more, in money and in disruption.

This is the kind of work we do as part of our proactive building management: regular inspections, planned maintenance, and finding the real cause of a problem rather than treating the symptom. You can read more about our services, or our practical guide to Fusiotherm leaks in apartment buildings.

If you would like a second opinion on how your building is set up for storm season, get in touch. The first conversation is short and no obligation.